Sensors of various kinds are known in the art. Some sensors respond to strain as imparted through mechanical pressure. One example of a known strain sensor comprises a thin metal foil disposed on a flexible substrate (comprised, for example, of polyimide material). The electrical resistance of such a strain sensor changes upon bending the metal foil and this change in resistance can serve as indicia of the corresponding strain.
Unfortunately, such embodiments are not wholly satisfactory for many purposes. For example, such sensors are readily damaged when extended too far. In general, such sensors work best when applied to a substantially flat surface. Affixing such a sensor to a given surface often requires a time-consuming process involving the application and curing of a suitable adhesive. And, at approximately five U.S. dollars or more per sensor, these prior art sensors are relatively expensive. Of course their cost becomes particularly commercially prohibitive as the number of sensors to be deployed on or with a given product increases.
As a result, such strain sensors tend to be used only relatively rarely and usually in circumstances where another kind of sensor will simply not suffice.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.